Rotary brush



March 1959 A. s. SWANSON ET AL 2,879,534

' ROTARY BRUSH Filed April 19, 1956 3 Sheets-Sheet l ywawraw 14L BERTJIJwn/vao/v fl4RL IE .ZK/MMERLE ,4 TTOP/VE/S A. s. SWANSON ETAL Mmflsi,1959 v Y b ROTARY BRUSH 6 5 9 1 9 1 1 1 m. A d e 1 i F 5 Sheets-Sheet 2March 31, SWANSQN ET AL 2,879,534

ROTARY BRUSH Filed April 19, 1956 5 Sheets-Sheet 3 5/ I UZZKW UnitedStates, Pa ent ,0.

ROTARY BRUSH Albert S. Swanson and Harlie J. Kimmerle, Minneapolis,

Minn., assignors to G. H. Tennant Company, Minneapolis, Minn., acorporation of Minnesota Application April 19, 1956, Serial No. 579,199

17 Claims. (Cl. --179) tips ranging from six inches upward to eighteeninches and even larger diameters and nominal axial lengths fromone tosix or even more feet are used. In such power driven maintenancemachinery, the rotary brush bristles may be of natural or artificialfibers and/or wire of fine or coarse diameters, the bristle materialsbeing used singly or intermixed. Power driven service to which suchbrushes are subjected is unrelenting and of heavy'or extreme loading andfrequently under adverse condition of wetness or humidity. It is to thisspecial class brush that the present invention is directed.

Heretofore in making such heavy duty rotary brushes it has beencustomary to provide a rotary reel frame, generally of wood or metalupon which the bristles (whether of fiber or wire) were carried by meansof separate carrier elements of wood or metal. Hence it has beencustomary to provide a rotary reel frame and upon it mount a pluralityof straight or spiral bar elements each carry,- ing one or more rows ofoutwardlyextending bristles, the bristles being attached by wirestitching or metal crimping in the case of metal bar elements or in thecase of wooden bar elements, by'wire stitching, stapling or cementing.Such brush assemblies composed as they are of separate rotary reel andbristle bar elemnts, are

sturdy, but expensive to manufacture, and the replacement onrehabilitation of such brush assemblies involve considerable down-timeand consequent cost, to say nothing of the replacement brush elementsrequired. In addition, such brush assemblies are heavy and cumbersometo' install, and require increased weight and sturdiness,

\ and hence cost of the machines of which such assemblies which 'utiliaes a hollowcore and which can be manufacr tured by rnethods heretoforeusable only for the manufacture Of, mall and light duty rotary brushesor brush stick elements. 7 v

Other and further objects are those inherent in the 2,879,534 rete dMar. 31, 1953 ICC.

' ends, this invention then comprises the features herein-'v theprinciples of the invention may be employed.

after fully described and particularly pointed out in the claims, thefollowing description setting forth in detail certain embodiments of theinvention, these being indicative however, of but a few of the variousways in whic The invention is illustrated in the drawings in which thesame numerals refer to corresponding parts and in which: I

Figure 1 is a side elevational view, partly sectioned along alongitudinalaxis, of a representative brush made in accordance with thepresent invention;

Figure 2 is an end view of the brush shown in Figure 1;

Figure 3 is a much enlarged view of several bristle tufts and a portionof the central brush tube core of a brush embodying the presentinvention, the tube being sectioned along .the longitudinal axis ofthebrush. This figure illustratesnatural or artificial fiber or straightwire material tor the bristles;

Figure 4 is a view similar to Figure 3, but showing varying forms ofbristle wire formation;

Figure 5 is an end view, similar to Figure 2 except that the tufts arearranged in rows with untufted spaces between rows. ,This figure alsoshows the brush cylinder while still mounted ,on the forming mandrel;

Figure 6 is also an end view, similar to Figures 2 and 5 except thattwice as many rows of bristles are shown as compared to Figure 5, andalternate rows are composed of different materials; and the mandrel hasbeen removed;

Figure 7 is a fragmentary planar representation of the brush tube asthough the tube were cut longitudinally and flattened. This figureillustrates the outer surface of the brush tube after drilling andbefore tufting, the pattern of location of the tnftholes beingexemplary;

Figure 8'is a much enlarged fragmentary sectional view, longitudinally'thru the brush tube and illustrating exemplary tufts while the brushtube is on the formation mandrel. This View illustrates for one tuft,the base of the tuft and the staple during the process of being placedand for another tuft, when the tuft and stable are secured;

and the attaching staple, which were forcibly pulled out of a brush forexamination.

It may be stated at the outset, that in the trade in which theinventions hereof form improvements of existing devices and methods,there is a certain confusion in nomenclature. In general, the subjectdevices are called f cylindrical or tubular brushes but this isfrequently a misnomer, because according to somemodes of manufacture nocylinder at all is used in the construction; thebrushes being held onsticks or elements or panels w' and assembled on some form of frameworkso that the bristles ends terminate to form a generally cylindrical.shape. -In other constructions the bristles are set on a; cylindricallyshaped center either solid or tubular. Un-' less otherwise stated, termcylindrical is used herein tb'j Figure 9 illustrates typical stapleshapes prior to setdenote the general overall shape of the completedbrush assembly.

Again such cylindrical brushes when separately considered, are spoken ofas having a certain diameter and length." Diameter is usually taken tomean the overall diameter of the brush, measured to the ends of thebristles, and will be understood herein to mean such overall apparentbrush diameter. The length of bristles protrusion beyond the support isusually spoken of as bristle trim. Length is usually taken to mean thenominal dimension of the bristled area measured at the bristle ends andparallel to the axis of rotation of the complete cylindrical brush. Theframework or central body on which the bristles are carried frequentlyextends in such axial direction beyond the effective bristledconfiguration to provide attachment facilities.

The above noted dimension length is completely lost when the rotarybrush is installed in the power machine in which it is used, and isreplaced by the term width, which, of course, refers to the width of thearea swept, scarified and/or polished by the brush as the brush isrotated and its axis translated in a direction parallel to the surfaceand generally normal to the rotational axis. For uniformity herein, theterm length, rather than width," will be used.

According to the present invention there is first prepared a multipleply paper tube which is built up by wrapping successive layers (turns)of paper on a cylindrical or tubular mandrel, the successive layers(turns) being held to each other by an adhesive. When the brush is usedunder wet or moist or humid conditions it is preferable that suchadhesive be waterproof or at least moisture resistant. Such multiple plypaper tube can be built up in several ways.

According to one method, successive strips ofpaper are spirally wrappedon a cylindrical mandrel, with a slight interturn space betweensuccessive turns of the spiral. Each spiral layer is wrapped on with agenerous lap over the interturn space of the layer below. Adhesive isapplied between turns, preferably by precoat ing the strip of whicheach' spiral wrap is composed. Successive layers are applied until thedesired tubular wall thickness is achieved. As a variation of thismethod, the spiral layers may be laid successively as right and lefthand (thread) spirals. According to still another method, a paper strip,of generous width is simply wound up turn upon turn until the desiredthickness is achieved.

Produced according to any of the aforesaid winding methods, thesuccessive layers (or turns) are held together tightly by adhesive,which, as stated, is preferably a waterproof or water resistant adhesivewhich, when relatively thin paper stock is used, may penetrate to someextent thru the thickness of the paper stock. Each turn is wound undertension and outer layers compressively stress the inner layers.

The paper that, according to this invention, is used to form the tube,is of tough and durable quality and may be single thickness orpaperboard stock ranging from 0.010" to 0.040" thickness. Penetration ofthe interturn adhesive, into the thickness of the stock, decreases andregions of negligible penetration are to be found between opposite facesof a layer, particularly where thicker stock is used. This is anadvantageous feature of the invention. Paperboard stock gives goodresults, but the use of higher quality stock and/or single sheetthickness, are not excluded.

Upon formation of the desired multi-layer tube, the built up tube isthen impregnated with a material capable of 'being hardened by drying,heating or chemically, or by acombination of these-factors. Weprefertoaccomplish impregnation by dipping the multiple layer tube component ina liquid phase heat hardenable material such as a varnish orresinpreferably of the type which ;is waterproof or moisture resistant. Forthis purpose, a phenolic resin in liquid phase such as phenolic resinsolution, may be used, the tube being dipped therein, after which it isbaked to harden the resin in situ. A wide variety of impregnatingsolutions may be used, the criteria being that reasonable penetrationinto the thickness of the multiple layer tube wall should be achieved;the impregnating material should be compatible with the paper stock andthe interturn adhesive and not produce deleterious effects thereon; theimpregnating material should harden either by drying, or bypolymerization, with or without heat, to harden and hence stiffen thoseportions of the tube into which the impregnant has penetrated. Where thecompleted brush is intended to be used in wet moist or humid conditions,it is, according to this invention, preferable to use as the impregnant,a material which is moisture resistant or water insoluble when set(polymerized). In this way there may be achieved a hardened andresistant tube surface and some increased hardness of the tube wall tothe extent of impregnation. Such hardness decreases with depth as thedegree of impregnation decreases.

While it is feasible to impregnate from only the outside of the tube,and such is within the purview of the invention, it is preferable,according to this invention, to impregnate the tube wall from the insideand outside, and this is easily accomplished by simply dipping the tubecomponents in the impregnating fluid. Impregnation of the tube from itsouter surface can easily be accomplished by dipping it into theimpregnating liquid while the tube is still on the mandrel. Whenimpregnation is desired from both the inner and outer faces of the tubewall the tube is pressed off the mandrel on which it has been formed andis then dipped to impregnate from both faces. The in-drawing of theimpregnating fluid by simple immersion is usually sufiicient, but deepimpregnation of thick-walled tube components composed of paperboard orpaper stock which resists penetration, may be accomplished more rapidlyby successive apv plication of vacuum and then pressure, while the com-'ponents are immersed in the impregnating fluid.

It has been discovered, according to the invention, that impregnationneed not, and preferably should not be completely thru the tube wall.The degree of impregnation decreases from the surface (at which theimpregnating material is applied) to the interior of the tube wallthickness.

After the impregnating fiuid has hardened there results a tubularcomponent having on the outer surface of its wall (or on its inner andouter surfaces, where impregnation is made from both surfaces), :1condition of maximum hardness and water resistances, and at successivelydeeper locations into the thickness of the tube wall, the degree ofhardness decreases, being a minimum at inside surface of the tube wall(where impregnation is from the outside only), or the degree of hardnessmay be a minimum at a zone about halfway between the inner and outersurfaces (where impregnation is from both the inner and outer surfaces).According to this invention, it has been discovered that such decreasingdegree of hardness at zones farther and farther removed from the surfaceto which the impregnating material is applied, is an advantage, and thedeepest zones may according to this invention be only slightlyimpregnated or be free from impregnation.

impregnation can be accomplished simultaneously with formation of themultiple ply tube by using paper stock which is relatively thin and byusing a generous amount of interturn adhesive, which then, in additionto serving as an adhesive, also penetrates into each layer from theadhesively coated surface and hence the adhesive serves as thepenetrating (or impregnating, however denoted) component. Varnish typeadhesives, many capable of being hardenedinto tough moisture resistantmaterials by drying or heating may thus serve not only as the adhesivebetween layers for holding the layers together but also as theimpregnation material by which the thickness i l l l i l l l i l iof...the -paper.stock in each layer, is impregnated and hardened. i.'The e'flect of impregnation (after hardening of the impregnating fluidor combined adhesive-impregnating agent) is several-fold. The tubestructure is made water resistant and hence durable under conditions ofmoisture and high humidity. fOf equal importance, the hardening effectof the impregnating material upon the fibrous structure of the multiplelayer paper tube, immensely facilitates drilling of the tuft holes. Itwas found that an unimpregnated multiple layer paper tube could bedrilled only with great difiiculty and that the paper tore, fuzzed, andwas not readily removed as chips from the holes. The drilling is done athigh speed and preferably with a drill that produces a hole in which theconical bottom approaches as nearly as possible a flat surface. lfn suchhigh speed drilling of a multiple layer paper tube which had not beenimpregnated, the holes were tom, the bit'lheated during drilling and bitlife was short. The holeswere irregular, fuzzy and full of paper residuechips. The same tube structure, but impregnated as herein described, wasdiscovered to be drillable at high speeds even with minimum impregnationatthe zones most removed from the surface of impregnation. The holes aresmooth, hard walled, the chips ejected cleanly. This islanadv antageofthe herein described invention.

"f'lhe' factor of decreasing impregnation at the deeper zones within thetube wall leaves unimpaired the tough and resilient and clinging fibereffect of the paper stock. This is found to be distinctly advantageousin respect to holding power of the staples that are used for holding thetufts. a

The hole size is varied within limits to accommodate the varying bristlematerial available. According to this invention the hole depth exceedsthe diameter'and the hole isdrilled, using a drill that produces a holebottom of shallow conical shape. This is desirable since a shallowconical bottom permits that portion of the tube under the hole to remainundisturbed and does not waste tube wall thickness which is needed foradequate setting of the staples. and depths is exemplary.

Tuft hole diameter, inches: Tuft hole depth, inches The tuft hole depthis measured at its deepest place in conical bottom. The bit shouldpreferably be sharpened so as to produce just as shallow a conicalbottom as consistent with adequate centering of the bit. The hold depth(HD, Figure 4) is always less than (preferably about 50% 4) andconsequently a generous underhole thickness (UHT, Figure 4) is alwaysprovided and is the stock into' which the staple penetrates and holds.According to this invention it has been found that a tube thickness (TT,Figure 4) of /2 inch to inch is adequate for most service but may beincreased to inch to 1.0 inch or more where the bristles are heavy orare of wire rope, or The under for largest sizes and heaviest dutybrushes. h'ole dimension can be increased by thickening the tube walldimension T1. The proportions in Figure 4 are not indicative. Y

, In drilling, high speeds (as for example 8000 to 12,000 r.'p. m.*) maybe used at the drill spindle. Good cutting of; the material is achieveddueto the hardening effect of the, impregnating material upon thefibrous structure of the paper; The impregnated material cuts well andthe hole' wall causes no undue drag upon (and hence heating of),.the bitand adequate throw-out of chips occurs. By contrash the drag of thepaper fibers in unimpregnated The following schedule of hole diametersto 75% of) the tube thickness (TT, Figure service the bristles are whichspiral around the tube.

eight rows .spacing between rows at S," a

This spaced row mode of bristle pattern distribution,

; different materials,

tubes of similar dimension so heats thejdrillas'to precludecommercial'operations and clean; accurate and chip free holes are notobtained. Also unimpregnated material fuzzes and does not drill cleanly,while holes in impregnated tubes, as herein described are clean andtrue, and

have strong walls.

Widely varying tuft holes patterns may be utilized,

The following are some eximpregnated paper tube, generally designated 10of V2 inch wall thickness and approximatelylS inches to '16 inches longhaving '32 rows of inch diameter, -1 inch deep tuft holes. Each rowcontains 40 holes making a total of 1280 holes (less 4 holes which areeliminated to allow the tube mounting slots 11 to be cut therein). The

. over-all diameter of this exemplary brush in 6.75 inches or statedanother way, the bristle trim is inch..

In this exemplary brush palmetto'fiberis used when For soft polishing,tamj pico fiber is used and for heavy polishing stifi tampico theservice is wet scrubbing.

fiber is used.

In another exemplary brush of larger power driven size and used forheavier service the central tube 10 may for example be 7 or 8 inches indiameter or even larger and of multiple ply constructed as. hereinbeforedescribed, impregnated and baked. For many types of preferably set inspaced rows staggered and close together, one row of bristles as at B-Bin Figure 5, these being separated by spaces S-S.v In Figure 7 each rowis a double row.

of bristles. As shown .in Figure 7, which is a developed view, there areshown double rows, the holes being staggered in each. double row?Forexample, double row'Rcontains two rows R1 and R2 in which the holesof one row are spaced'between those of the companion row. The entiredouble row preferably spirals as for example N for the example shown.Thus a spiral of in 36 inches of brush length L gives good results. Thehole size and depth of the tuft holes is chosen according to the bristleused and the service intended. Each double row produces acircumferential width of bristles (in the row) of dimension B, and theFigure 5, thus results.

produces excellent results for sweeping and trash pickup and scarifying,particularly, general service.

For other service, as: general service and polishing a larger number ofrows of bristles is .usually desirable, as shown in Figure 6. severalclosely spaced rows, as in Figure 7, and are curved to spiral. In Figure6, alternate rows can be of ple monofilament plastic bristles) and wirein alternate rows, or natural bristles (example tampico or bassine)andwire in alternate double rows; or artificial fibers and 1 naturalfibers in alternate rows.

As further exemplifying the invention but not by way-- of limitationseveral large size power driven brushes are;=

specified herein. In the following example several types of basictubesare specified, along exemplary brush specifications therefor, asfollows:

Basic tube A.--Tubes 15 or inches ID; 7% inches vO.D.;

resin impregnated (from inside and outside of the tube Multiple" rows ofholes; considered together form Thus referring to Figure 5, tube'15 hasbut it is also useful in somev I The rows are usually composed of as forexample artificial fiber (exam- 17 (Figures 5 and 6) 6% thickness(TT,.Figure 4) I /5 inch;- length 36 inches; 25 plys 0:020 inch thickpa'per-' v board stock; waterproof adhesivebet ween plys; phenolicasking. -HOiesdfilled in donblerows; 146 holes inch dia. x i inch deepor big inch dia. x inch deep (depending on fineness of bristles) perrow; spiral 90 in 36 inches;total holes: 8 double rows, 1168 holes; 16double rows, 2336 holes.

For polishing: The aforesaid basic tube A having 16 double rows tampico,bristle trim 2 inches to 3% inches.

For general purpose sweeping: The aforesaid basic tube A, 18 doublerows, mixed bristle tufts (union mix) of tampico and bassine, bristletrim 3% inches, 8 double rows.

For sweeping: The aforesaid basic tube A; monofilament chemicallyresistant polystyrene (or nylon or Briston etc. may be used where costsdo not impede); bristle trim 3 /4 inches; 8 double rows.

For light sweeping: The aforesaid basic tube A horsehair; 16 doublerows; 3% inches bristle trim.

For heavier service the following examples may be given by way offurther exemplification, but not as a limitationupon the invention.

Basic tube B.Tube 15 or 17 (Figures 5 and 6) 6 /2 inches I.D.; 7% inchesO.D.; wall thickness (TT Figure 4) inch; plys 0.020 inch (or thicker orthinner plies to make approximately an equivalent thickness); waterproofadhesive between plies impregnated (from the inside and outside of thetube wall) by dipping in phenolic resin liquid and then hardened andpolymerized by baking. Holes drilled in double rows, either 8 doublerows or 16 double rows. Hole diameters and depths depending upon bristlematerials, diameters and depths as hereinbefore specified; 100 .holes ineach double row (staggered, as in Figure 7); 90 spiral per 36 incheslength; total holes approximately 800 for 8 double rows; approximately1600 for 16 double rows.

For light scarifying: basic tube B, 8 double rows; 30 gauge steel brushwire .014 inch dia., the wire being slightly kinked at 1% inch to 7 inchintervals as shown in Figure 4; bristle trim 3% inches.

For heavy sweeping: basic tube B, 8 double rows; 4 double rows steelbrushwire as in the preceding paragraph alternating with 4 double rowsnonfilament chemically treated polystyrene (Algil); bristle trim 3%inches.

Figure 4 shows two tufts composed of wire, preferably steel wire. Theright hand tuft is composed of brush wire of appropriate gauge which iskinked slightly (15 to 30") at intervals of /a inch to inch. Thelefthand tuft in Figure 4 is composed of wire rope bristles, the ropebeing composed of brushwire spirally twisted I0 gether.

In all the foregoing examples the bristles of each tuft whether naturalor artificial fiber or wire or mixtures thereof, were held by staples,set as hereinafter described. The, staples were cut from steel staplewire which may range from 26 ga. (0.181 inch) for light bristlematerials and light service to 14 ga. (0.080) for heavy bristlematerials and heavy service. 18 ga. (0.0475 inch) staple wire issatisfactory and produces good results in most applications.

Reference is now made to those figures of the drawings which show thestaples, particularly Figures 1, 3, 4, 8, 9, l0 and 11. According tothis invention it has been discovered that adequate holding power of thestaples in large, power driven, cylindrical brushes can be achieved byutilizing as the core of a multiple ply paper or paper board tube, madeas hereinbefore described and impregnated and baked. With such a tubecomponent the holes are drilled and the tufts of bristles are thenformed and the staples cut and set by suitable machine or by hand.Machine stapling is preferred for economy and can readily-beaccomplished by utilizing the specifications and methods hereinset-forth.

- Figure 9 shows the typical staple shapes before setting. In Figure.are shown typical stapleshapes after setting and after withdrawing worntufts and'st'aples from a-worn out brush. Stapes 2024 were from a heavyduty brush with wire bristles, used in scarifying service. 'T he staples20-24 are widened and levelled out at their tops, and are closed (tovarying degrees) at their lower ends. Most are blunted (clinched) tosome degree on at least one tine, and in all except one (24) the tinesare bent sideways to some extent. Staple 25 was for a union mixturebrush (tampico and bassine) and it is also spread at the top. Thediameter of the holes in which these staples (and the bristles heldthereby) were set are shown by the approximate dimension D adjacent thetop of each staple illustrated in Figure 10. In every case, the settingof the staple by the staple driver acts to spread the top as the stapleis driven and the tines thereof penetrate the underhole thickness (UHT,Figure 4) and reach or nearly reach the inner surface of the tube duringsetting. The resistance to penetration incerases as the staple is drivenand the staple driver (which is straight across at its lower end)straightens out the top of the staple and spreads the tines apart andagainst the hole walls. In so doing the staple holds four ways i.e. (l)by spreading of its top part against the hard (impregnated paper)sidewalls of the tuft hole; (2) by the tenacity of the impregnated paperfibers gripping the tines, (3) by clinching of one or both tines, and(4) by a certain amount of bending of the tines as they penetrate thetough paper tube stock.

In many instances both staple tines will not reach all the way into theinner surface of the tube wall. Figure 11 illustrates two tufts of unionmixture (bassine and tampico fibers) and their staples which wereforcibly pulled out of their tuft holes. In the tuft 26, staple 27 hasnearly closed its tines together and one tine penetrated deeper than theother. In tuft 28 staple 29 did not close so much. In respect to eachtuft shown in Figure 11, the tuft hole diameter is approximately shownby the dimension D. In each instance the head of the staple wasstraightened sufficiently to cause it to spread at the head and thoseportions of the tines adjacent the head were forced to bite into thetuft hole sidewalls thus providing great holding power. In each instancethe holding power was entirely adequate for the tufts shown in Figure11.

Figure 8 illustrates the mode of setting staples and Figures 3, 4, and 8illustrate the set staples. In Figure 8 the thickness of the wall oftube 50 is shown by the dimension TT. This thickness is here made up oftwelve plys of paperboard stock held together with waterproof adhesiveand then impregnated by dipping in phenolic resin solution, drying andbaking to set the resin. No attempt is made in Figure 8 to show thedegree of impregnation. In placing the tufts and staples tube 50 issleeved on mandrel 51 which is a diameter slightly less than the insidediameter of the tube 50 so as to leave clearance 52 which may beslightly irregular since the tube 50 does not always remain perferctlytrue to diameter on the inside. Also the clearance 52 facilitatessleeving the tube 50 onto the mandrel 51 and particularly facilitatesits removal after tufting is completed since clinching of the staplesproduces some irregularity on the inside of the tube. The holes aredrilled to depth HD and this leaves an undistrubed zone at 54 ofthickness UHT, as previously mentioned. In machine setting the staple 53is cut chamfered in one direction at 55 and in the other direction at56. The bristles 60 in adequate number to provide good filling of thetuft hole are looped by the curved head staple 53 and drawn downinto'the hole as the staple is driven. For tuft 62 the staple points arejust entering zone 54 and the oppositely chamfered points 55 and 56 tendto cause the staple legs 53A" and 5315 to assume a twist and topenetrate into the tube" in slightly differing directions, which isdesirable butnot essential.

Experience shows that widely different staple "penetration patterns ofthe staple tines will occur without'dele I l i l terious results. Theillustrations herein are therefore to 'be cons'idered as exemplary. f;

1 As penetration of the tines 53A and 53B continue the resistance topenetration increases and the flat bottom staple driver (not shown),which engages against the curved head "53H of the staple causes it tobecome s'quared out" to some degree. Clinching, as shown for staple63'of tuft 65 can of course occur only when the tines 63A and 63B of thestaple are sufiiciently long and pursue a direction to reach thru theunderhold diniension UHT and strike the mandrel 51, and while,

according to this invention, clinching is regarded as desirable, goodresults are also obtained when the underhole thickness is great enoughto allow complete penetration of the tines without clinching.

Squaring of the heads of the staples always occurs at 63H to some extentand pushes the corners 63K-63K into the tuft hole sidewalls. This isbelieved to be due to the resistance to penetration offered by thestaple tines as they penetrate, even without the extreme resistance topenetration encountered in clinching.

The seated staple is exemplified for tuft 65, and it will be noted thattines 63A and 63B are clinched at 63C63C. Some roughness or slightlumpiness therefore is evident on the inner surface of the tube wall butit is not a disadvantage. The tube 50 has sufficient resiliency to takeup clearance 52 and settle upon mandrel 51 as the staple is set, toallow adequate clinching, where the staple dimensions, underholethickness UI-IT and volume of tuft materials is such as to permitclinching penetration.

For wire bristles, it is, according to this invention preferable toemploy wire which is slightly prekinked or gently spiralled. This is afeature of the invention. It is found that in most cases, life of wirebristle brushes is much increased by this expedient. This expedient may,

also be used with good results with many plastic bristles, particularlyin respect to those showing a tendency to failure in fatigue, and thisis a feature of this invention.

According to this invention the completed and tufted brush may be dippedinto a coating solution, drained and baked or otherwise treated to dry,consolidate (polymerize) the coating. This provides repenetration of thecoating solution into the drill holes; it seals the tuft holes andprovides corrosion resistance particularly for ferrous wire bristleswhich are required to operate under humid or wet conditions. As thecoating solution there may be used varnish or drying or polymerizingresin in solution. Any compatible resins may be used, such as phenolicresins, polyamide resins, urea resins, melamine resins and the like.When applying such dipcoating, it is desirable to subject the submergedbrush to successive vacuum and pressure to draw out air from the tuftholes and hence allow the dip-coating to penetrate deeply into the baseof the tufts in the tuft holes. The clipped brush may then be spun tospin off excess dipcoating fluid and then dried with heat. This providesgood protection deep in the tuft holes right down to the base of thetufts.

No attempt has been made herein to illustrate the various keying devicesor shapes that can be used for transmitting the rotation power forces tothe tube of Figures 1 and 2; 50 of Figure 8). In Figures 1 and 2 thereare shown slots 11--11 which are engaged by the brush drive mechanism torotate the brush. It will be understood that these are merely exemplaryof any form of surface or protuberance on or attached to the tube forrotating the brush.

It is apparent that many modifications and variations of this inventionas hereinbefore set forth may be made without departing from the spiritand scope thereof. The specific embodiments described are given by wayof example only and the invention is limited only by the terms of theappended claims.

sa g s wrsl im a 9 i ven b p rotary cylindrical brush 'foi' ipoweifpolishers, scaritiers and the like comprising a cylindrical tubecomposed of a plurality of plies of paper wound tightly, one layer uponanother and held together ad hesively, said tube being impregnated witha hardenitig agent, the amount of impregnation gradually decreasing in adirection away from the surface of said tube, said tube having" aplurality of holes drilled thereinto from its exterior surface andpartly thru the tube wall thickness, and tufts of bristles stapled into.said holes.

2. The brush. defined in claim 1 further characterized in that theadhesive between plies is water resistant.

3. The brush defined in claim 1 further characterized in that thehardening agent is a polymerized plastic.

4. The brush defined in claim 1 further characterized that the hardeningagent is a heat hardening plastic.

5. The brush defined in claim 1 further characterized in that said tuftholes are in spaced rows extending substantially from end to end alongthe cylinder and slightly spiralled.

6. The brush defined in claim 1 further characterized in that said tuftsof bristles are composed of natural bristle fibers.

7. The brush defined in claim 1 further characterized in that saidcylinder is provided with a keying surface shaped so as to be engageableby a driving device for rotating the brush about the cylindrical axisthereof with power.

8. A cylindrical brush for large power driven sweeping, polishing,scarifying and the like machines comprising a multiple layer built uppaper tube greater than substantially 4 inches in diameter and a lengthof greater than substantially one foot composed of plies having athickness of from 0.010 inch to 0.040 inch thickness, said plies beingsecured together with adhesive, said tube material being impregnatedwith a hardened impregnant, the amount of impregnation being graduallydecreased at positions of increased distance from a surface of the tubesaid tube being provided with rows of tuft holes extending from theouter surface of the tube and partly thru the tube wall and bristlestapled into the bottom of said tuft holes, said brush having an overalldiameter of more than 5 inches at the bristle tips and a length of morethan 12 inches, said staples being spread at the top into engagementwith the walls of the tuft holes.

9. The brush defined in claim 8 further characterized in that theadhesive and hardened impregnant are waterproof.

10. The brush defined in claim 8 further characterized in that thebristles are ferrous wire.

11. The brush defined in claim 8 further characterized in that thebristles are prebent ferrous wire.

12. The brush defined in claim 8 further characterized in that theentire brush has a hardened dip-coating of protective material thereon.

13. The brush defined in claim 1 further characterized in that saidtufts of bristles are composed of plastic fibers.

14. The brush defined in claim 1 further characterized in that saidtufts of bristles are composed of metallic wire.

15. The brush defined in claim 1 further characterized in that saidtufts of bristles are composed some of natural bristle fibers and someof metallic wire.

16. The brush defined in claim 1 further characterized in that saidtufts of bristles are composed some of non-metallic fibers and some ofmetallic wire.

17. A rotary cylindrical brush for power sweepers, polishers, scarifiersand the like comprising a cylindrical tube composed of a plurality ofplies of paper wound tightly, one upon the other so as to form a thickwalled tube, said tube being impregnated with a hardening agent, theamount of impregnation at positions on the interior of the tube wallbeing less than on the surfaces of the tube wall, said tube having afilura'lity of holes thereinto from the exteriorsurface of the tube wallbut only partly 't he'rethrough so as'to leave a portion of the tubewall forming bottoms of said holes, and tufts of bristles in said holes,said tufts being held in place with staples 5 driven into the bottoms ofsaid holes.

References Cited in the file of this patent UNITED STATES PATENTS ReadJan. 4, 1898 Richards May 1, 1900

